I don't have many suggestions besides the ones you listed, but I can offer that the things that work for me now did not seem to work at the beginning. When T started progressive muscle relaxation with me, I was upset because it didn't calm me down. He said that was too big a goal--we were just trying to relax me a very tiny bit more than I was when I started. When I made that my goal, I found that things like yoga, physical exercise in a contained environment like a gym, and meditating while I did artwork could all make me a tiny bit more relaxed. Over time the effect increased and now they are pretty effective. For me the key is being able to find something that will absorb my attention.

I empathize because I know that freeze/run feeling is rough. It can get better, though.